The 2019 Hyundai Sonata features 4-cylinder engines—the 2.4L or 2.0L turbo—in most configurations. These inline-4 engines contain only cylinders 1 through 4. When P0306: Cylinder 6 Misfire Detected displays, you're facing an anomalous code on 4-cylinder models.
Final Seventh-Generation Sonata
The 2019 Sonata was the last year of the previous generation and the last to offer V6 availability. If your 2019 Sonata has the 4-cylinder engine, P0306 is anomalous. The 2.0L V6 option (if equipped) would make P0306 a valid code requiring diagnosis.
Determining Your Engine
Check your Sonata's VIN or underhood sticker to confirm engine type. The 2.4L and 2.0L turbo are 4-cylinder; the 2.0T V6 Limited makes P0306 valid.
Diagnostic Approach
For 4-cylinder models, clear codes and use Hyundai GDS for accurate readings. Check for valid misfire codes (P0301-P0304). If you have the rare V6 model, proceed with standard cylinder 6 misfire diagnosis.